Table 3.
Risk ratios comparing the number of spontaneous deliveries in the weeks after the transition out of daylight saving time (autumn) with the mean number of spontaneous deliveries in the week before and the week after this period
| Comparison unit | Number of spontaneous deliveries |
RR (95% CI) | |
|---|---|---|---|
| Observed* | Expected† | ||
| Whole week | 19 072.9 | 19 122.0 | 0.997 (0.983 to 1.012) |
| Sunday‡ | 2617.9 | 2703.5 | 0.968 (0.932 to 1.006) |
| Monday | 2841.0 | 2862.0 | 0.993 (0.956 to 1.030) |
| Tuesday | 2720.0 | 2782.5 | 0.978 (0.941 to 1.015) |
| Wednesday | 2708.0 | 2770.0 | 0.978 (0.941 to 1.015) |
| Thursday | 2812.0 | 2685.0 | 1.047 (1.009 to 1.087) |
| Friday | 2690.0 | 2755.5 | 0.976 (0.940 to 1.014) |
| Saturday | 2684.0 | 2563.5 | 1.047 (1.008 to 1.087) |
*Observed is the number of spontaneous deliveries during the week following the autumn transition.
†Expected is the number of spontaneous deliveries during the week before and the week after the week following the spring transition divided by two.
‡The number of deliveries on the Sunday following the transition out of daylight saving time was adjusted for the longer day length (25 instead of 24 hours).
CI, confidence interval; RR, risk ratio.